Wasn't Tangerine Rd (unsigned AZ 989) meant to be the northern part of a beltway?
Tangerine seems a bit far out (to the N) to have been part of a limited access beltway. Yet there it is on that planning document from decades ago. Maybe? it was envisioned as an expressway type route. Did do some asphalt sampling about 15 months ago on the "four laning" or "boulevardization" of it. This was E of Interstate 10.
Back in the day, would have attempted to run a facility (similar to Calif's I-210) along the foothills to Houghton, then turning S to rejoin 10 at a stack interchange. Box beam or segmental.
Then continuing S and then W to meet 19. With a high speed T type of interchange, again, of box beam or segmental flyovers. Then, the foothills, and Houghton, were empty, today the foothills are filled with millionaire housing.
Kino Parkway, yesterday's 710, would have been a useful stub to access the University from 10.
Aviation-Barraza, or AZ 210 believe was supposed to penetrate downtown, but in recent times, does not seem very likely. A 810 designation would have been more appropriate, had it ever been able to meet 10 at both ends.